As anyone familiar with climate history knows, the earth has been locked in ice ages for 90% of the past 2 million years, with huge temperature swings and mile high glaciers over what are now northern American cities like Seattle. Every hundred thousand years, there is a roughly ten thousand year warm period, which we are at the far end of now.
This article summarizes this history, and is a good reminder of how really ignorant the global warmers are. Human CO2 production, though it is a small percentage of natural CO2 emissions, may be the only thing we can do to delay the onset of the inevitable plunge in temperature that awaits us.
The sun is in a very unusual quiet period which has been linked to past temperature declines, and temps have been falling for the past several years. While this decline is unlikely to be "the big one," it is coming, and humanity will have to use all its technological capacity to avoid the catastrophic impact it is likely to have on food production and everything else modern civilization provides.
Spending trillions to reduce CO2 emissions is a huge step in the wrong direction.